Modern gas turbines, particularly aircraft engines, must satisfy the highest demands with respect to reliability, weight, performance, economic efficiency and durability. In the last decades, aircraft engines were developed, particularly in the civil sector, which fully satisfy the above requirements and have achieved a high degree of technical perfection. Among other things, the selection of materials, the search for new suitable materials and the search for new manufacturing methods and repair methods play a decisive role in the manufacture and also in the repair of aircraft engines.
Numerous methods for manufacturing and repairing components for gas turbines are conventional. This includes, among other things, forging and investment casting. Thus, conventionally, all highly stressed components in the compressor region of a gas turbine are manufactured by forging, whereas the rotor blades, for example, as well as the stator blades of the turbine are investment casting parts. Particularly milling from the solid or joining of finished blades to a rotor holder or a hub by linear friction welding are used in the manufacture of gas turbine rotors having integral blading, of so-called blisks (bladed disks) or blings (bladed rings).
Another conventional method for manufacturing and repairing or restoring blades for gas turbines is the so-called laser-powder build-up welding, which is also called laser beam build-up welding or laser beam generation. Conventionally, laser-powder build-up welding is used particularly in maintenance work and restoration work. Thus it is conventional for blades, which have a short blade length as a result of wear, to be restored by laser-powder build-up welding so that the blades may be reinstated more frequently and consequently do not have to be sorted out prematurely.
A method for manufacturing or restoring blades for turbo engines by laser beam build-up welding is described in German Published Patent Application No. 195 47 903. In the method disclosed therein, a strip of sheet metal is used as a support form. Following the extension of the blade by laser build-up welding, the sheet metal strip is removed and reused.